Colorimetry at NHK Opticians

exceptional reading


Colorimetry is a proven vision therapy using coloured overlay sheets and precision tinted prescription lenses to help with undiagnosed reading difficulties. Jumping words? problems tracking lines of text? visual stress? Colorimetry could help . . .

Whether you are a teacher, parent or learning support specialist you will know that solving undiagnosed reading difficulties can be time consuming and often frustrating, especially when conventional therapies fail to yield the results you had hoped for. It is often assumed a child or young adult is simply dyslexic, but are they?


There is an increasing body of evidence that suggests some children, young adults and even adults may be experiencing a form of visual disturbance caused by the way their brain processes visual information when they read: losing track while reading, becoming very tired and showing fear or reluctance to read.


Over the last three decades a form of Therapeutic Optometry known as Colorimetry has been developed to offer relief with some undiagnosed reading difficulties.

Initial Coloured Overlay assessments are available at all our practices.

Colorimetry is currently offered at our Callington, Ivybridge and Carbis Bay practices.


coloured overlays


The initial stage is with the use of coloured overlay sheets. Assessment usually involves an appointment to see if they might be beneficial. Occasionally the Optician may carry this out at the same time as an Eye Examination but more often than not it is a separate appointment.

Assessment involves the measurement of reading speed both with and without overlay assistance using a standardised piece of text printed black onto white and held at a set distance from the patient.

colorimetry assessment


If coloured overlays prove beneficial, a more detailed assessment using an Intuitive Colorimeter is recommended. This utilises the same reading speed test but builds on the initial overlay result; for example say a light green or dark green overlay sheet, by further defining a precise hue and saturation of that colour. By fine-tuning the colour specifically to the individual it’s effectiveness can be greatly improved upon. 


fees and charges

Regretfully, at present, the NHS does not provide specific assistance for assessment and supply of coloured overlays or colorimetry glasses. Some local colleges also help out with costs.

However if you have a prescription and normally receive an NHS voucher towards your glasses, this voucher can be used towards the cost of colorimetry glasses.

colorimetry glasses

The colorimetry assessment produces a unique and highly accurate pure precision tint specification that can be subsequently applied to ophthalmic quality spectacle lenses and mounted into a frame. The resulting colorimetry glasses often prove to be a far more convenient solution for long-term use with the added advantage of any prescribed prescription also being incorporated into the glasses.


Members of:  International Institute of Colorimetry and Cornwall Dyslexia Association